SANTIAGO, March 16 (Reuters) – Chile's new government is evaluating whether to support a petition filed by its predecessor to block the sale of a stake in top lithium miner SQM to a Chinese firm, a senior government official told Reuters on Friday.

Chile development agency Corfo filed a complaint last week to block the sale of a 32 percent stake in SQM to China's Tianqi Lithium or any related entities or state-backed firms, saying it would "gravely distort market competition."

The move was the latest in a battle to secure lithium, a major ingredient in rechargeable batteries for electric vehicles, mobile phones and tablets.

Corfo, which oversees SQM's holdings in the lithium-rich Salar de Atacama region in northern Chile, filed the complaint with anti-trust regulator FNE just two days before conservative billionaire Sebastian Pinera took office as president on March 11.

"We have not made a decision (to support or not support) in this case," the government official told Reuters, speaking on condition of anonymity. "In this case, in particular, we must closely analyze the consequences."

Pinera won a landslide victory in December on a pro-business platform, and his one-week old government has promised to boost investment and cut red tape after years of stagnant growth.

Regulator FNE has as long as six months to decide whether to open an investigation in the case.

It was unclear if Corfo's complaint, if upheld, would block all potential Chinese bidders for the stake, including those that are not state-backed.

"It's an issue we need to assess," the government official said. "The policy of Chile, in general, is to not block {such transactions} by nationality."

The Corfo complaint does, however, make clear that Tianqi specifically should be forbidden from purchasing the stake.

Eduardo Bitran, then head of Corfo, said in an interview last week that Tianqi Lithium presented a "non-binding" offer for Nutrien Ltd's 32 percent stake in SQM, worth about $5 billion.

The offer was more than 20 percent over market value at the time it was presented, when SQM shares had reached all-time highs, Bitran said.

Corfo's complaint centers on concerns that, together, Tianqi and SQM, the world's second-biggest lithium producer after U.S.-based Albemarle Corp, would control 70 percent of the global lithium market, according the document.